A new podocnemidid (Pleurodira: Pelomedusoides) from the Eocene of north-western Argentina, with comments on its evolutionary relationships and palaeoenvironmental settings

We report a new small podocnemidid, Gestemys powelli gen. et sp. nov., based on one nearly complete skull, lower jaw, two shells, and remains of the appendicular skeleton belonging to specimens from Eocene Geste Formation San Antonio de la Cobres Basin, Salta Province, north-western Argentina. As in other podocnemidid genera, exhibits fully developed medially extensive cavum pterygoidei, an incisura columellae auris enclosing stapes Eustachian tube, lacks exoccipital quadrate contact. bears huge foramen palatinum posterius short pterygoid flange that does not reach basisphenoid suture, exposing pterygoid. Phylogenetic analyses place as member Podocnemididae more closely related Erymnochelyinae than Podocnemidinae. In regards palaeoenvironmental settings Palaeogene formations (Maíz Gordo Geste) Argentina, at least features differentiate palaeoenvironment where G. was recovered those turtles Maíz Formation: 1) found situ with very little re-working; 2) contrast muddy rocks indicating marginal lacustrine setting humid climate Formation, is associated coarse-grained floodplain dry, temperate climate. Such differences highlight contrasting environmental dynamics which lived during Palaeogene.http://zoobank.org/urn:lsid:zoobank.org:pub:0E631DA2-053F-4BD6-91BD-2401F34A5777